Although a fever could be considered any body temperature above the normal 98.6 F (37 C), medically, a person is not considered to have a significant fever until the temperature is above 100.4 F (38.0 C).
Most fever is beneficial, causes no problems, and helps the body fight off infections. The main reason to treat a fever is to increase comfort.
Fever is the result of an immune response by your body to a foreign invader. Foreign invaders include viruses, bacteria, fungi, drugs, or other toxins.
Children under 3 months of age with a temperature of 100.4 F (38.0 C) or greater should be seen by a health-care professional. They may be quite ill and not show any signs or symptoms besides a fever. Infants younger than 6 weeks of age should be seen immediately by their doctor.
Acetaminophen (Tylenol and others) and ibuprofen (Advil, Motrin) can be used to treat a fever. Aspirin should not be used in children or adolescents to control fever.
The prognosis for a fever depends on the cause. Most cases of fever are self-limited and resolve with treatment of symptoms.
A person who is taking immunosuppressant drugs or who has a history of or diagnosis of cancer, AIDS, or other serious illness, such as heart disease or diabetes, should seek medical care if a fever develops.
Troublesome Fever Symptoms
Although, if the fever is accompanied by any other troubling symptoms, you may need to see your doctor to be certain. As fevers range to 104 F and above, however, there can be unwanted consequences, particularly for children. These can include delirium and convulsions.